Cameron Dean, left, and Dennis Smith watch runners make their way down 18th Street during the annual Santa Skivvies Run Sunday, Dec. 16, 2012. Four hundred volunteers and joggers took part, raising $43,000 for the AIDS Foundation. Runners started at the Lookout Bar on Market Street then ran through the Castro District taking a spontaneous route, much to the delight of onlookers.

Runners pass David Pritikin, a traffic Elf who stopped cars on Noe Street in the annual Santa Skivvies Run Sunday, Dec. 16, 2012. Four hundred volunteers and joggers took part, raising $43,000 for the AIDS Foundation. Runners started at the Lookout Bar on Market Street then ran through the Castro District taking a spontaneous route, much to the delight of onlookers.

Runners pose for photos prior to the start of the annual Santa Skivvies Run Sunday, Dec. 16, 2012. Four hundred volunteers and joggers took part, raising $43,000 for the AIDS Foundation. Runners started at the Lookout Bar on Market Street then ran through the Castro District taking a spontaneous route, much to the delight of onlookers.

Photo: Lance Iversen, The Chronicle

Runners pose for photos prior to the start of the annual Santa...

Runners pose for photos prior to the start of the annual Santa... Photo-3902693.53999 - SFGate

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Runners in the annual Santa Skivvies Run try to stay warm prior to the start Sunday, Dec. 16, 2012. Four hundred volunteers and joggers took part, raising $43,000 for the AIDS Foundation. Runners started at the Lookout Bar on Market Street then ran through the Castro District taking a spontaneous route, much to the delight of onlookers.

Runners make their way down Noe Street in the annual Santa Skivvies Run Sunday, Dec. 16, 2012. Four hundred volunteers and joggers took part, raising $43,000 for the AIDS Foundation. Runners started at the Lookout Bar on Market Street then ran through the Castro District taking a spontaneous route, much to the delight of onlookers.

Photo: Lance Iversen, The Chronicle

Runners make their way down Noe Street in the annual Santa Skivvies...

Runners make their way down Noe Street in the annual Santa Skivvies... Photo-3902705.53999 - SFGate

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Runners make their way down Noe Street during the annual Santa Skivvies Run Sunday, Dec. 16, 2012. Four hundred volunteers and joggers took part, raising $43,000 for the AIDS Foundation. Runners started at the Lookout Bar on Market Street then ran through the Castro District taking a spontaneous route, much to the delight of onlookers.

Photo: Lance Iversen, The Chronicle

Runners make their way down Noe Street during the annual Santa...

Runners make their way down Noe Street during the annual Santa... Photo-3902696.53999 - SFGate

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Natalie Lewellyn and her child Misha, age 2, look on as four hundred volunteers and runners took part in the annual Santa Skivvies run that raised $43,000 for the AIDS Foundation, in San Francisco, Calif., Sunday, Dec. 16, 2012. Joggers started at the Lookout Bar on Market Street then ran through the Castro district taking a spontaneous route, much to the delight of onlookers.

Photo: Lance Iversen, The Chronicle

Natalie Lewellyn and her child Misha, age 2, look on as four...

Natalie Lewellyn and her child Misha, age 2, look on as four... Photo-3902689.53999 - SFGate

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Santa Skivvies runners stand in line to get into the Lookout Bar on Market Street after they took part in the annual run that raised $43,000 for the AIDS Foundation, in San Francisco, Calif., Sunday, Dec. 16, 2012. Joggers started at the Lookout Bar on Market Street then ran through the Castro district taking a spontaneous route, much to the delight of onlookers.

Photo: Lance Iversen, The Chronicle

Santa Skivvies runners stand in line to get into the Lookout Bar on...

Santa Skivvies runners stand in line to get into the Lookout Bar on... Photo-3902701.53999 - SFGate